The Mouse Pathology and Imaging Core will be established to provide the necessary facilities and faculty and staff expertise to support all four of the research projects. A major goal of the Core will be to provide expertise in mouse pathology with a specific focus on detailed aspects of thyroid gland pathology, including the pathobiology of mouse thyroid carcinoma. Pathology support will be provided by veterinary anatomic and clinical pathologists that are Diplomates of the American College of Veterinary Pathologists. Expertise in comparative thyroid gland pathology will enable appropriate interpretation and evaluation of the mouse models in the research projects and comparison to human thyroid cancer. In addition, a Veterinary pathology postdoctoral trainee in mouse pathology will perform the mouse necropsies (autopsies), cutting and processing of tissues and evaluation of histopathology under the supervision of faculty pathologists. This will provide excellence and continuity of service for the research projects, and allow consistency and high level integration of pathologic changes observed in the differing mouse models used in this project. Additionally, this core will serve the purpose of coordinating and integrating various imaging modalities, including anatomic imaging such as Faxitron high resolution radiography, micro computed tomography (microCT), and, high frequency ultrasound imaging of mouse thyroid glands. Functional imaging capability is also available, including whole animal or organ bioluminescent and fluorescence imaging and combined microCTradioisotope imaging of mouse thyroid tumors. Other services that will be available to investigators include (1) mouse clinical pathology, including a full-service hematology and clinical chemistry laboratory in the Veterinary Medical Teaching Hospital that can appropriately analyze blood samples from mice; (2) support for studies on metastasis including orthotopic implantation of tumor tissue into the thyroid bed and injection of tumor cells into the tail vein and/or left cardiac ventricle to induce metastatic disease. Facilities will include four necropsy rooms, an automated Dako immunostainer, microcopy facilities including a 10-headed microscope with video output for conferences, dedicated bioluminescent and fluorescent in vivo imaging instrumentation, dedicated high resolution (30 urn) ultrasound equipment for small animals, digital gross and microscopic photography facilities, histomorphometry equipment including a fluorescent microscope and Bioquant Nova analysis software, mouse surgery and radiology facilities. Because the science in this project is spread among various models and physical locations, the availability of a single core to coordinate, analyze, and compare data will provide an essential resource and significantly enhance the quality and validity of the research data.